Stem cell therapy is an exciting area of multiple sclerosis research. Interest in the potential of stem cells to improve multiple sclerosis by slowing down the disease and repairing damage to the nervous system continues to grow in the MS research community. However, it can be confusing to know what is discussed when “stem cells” are mentioned in the news or scientific publications.
Stem cell therapy itself is not entirely new, but use in MS is still experimental and no therapies have been approved in the United States. There are important ongoing clinical trials in the US and a number of patients have traveled abroad to receive treatment. Patients need to be cautious, however, because of the numerous bogus and unscrupulous “stem cell clinics” who heavily recruit patients for their treatments.
What is cell-based therapy?
“Cell-based therapy” refers to the transplantation, delivery or stimulation of various cell types for the purpose of treating MS. It is important to know that there are a variety of cell-based therapies used in MS. To discuss the state of stem-cell research, more than 70 experts convened a meeting - the International Conference on Cell-Based Therapy for Multiple Sclerosis - held in Lisbon and hosted by the National MS Society, ECTRIMS, and Multiple Sclerosis International Federation (MSIF). Progress was reviewed related to the value of specific cell types, including hematopoietic stems cells (derived from the bone marrow), mesenchymal stem cells (derived from many different adult tissues), and oligodendrocyte precursor cells (derived from multiple sources).
What is hematopoietic stem cell transplantation (HSCT) therapy?
Hematopoietic stem cell transplantation (HSCT) involves the intravenous (IV) infusion of autologous (from same individual) or allogeneic (from donor source) stem cells to reestablish hematopoietic function in patients whose bone marrow or immune system is damaged or defective. HSCT therapy is used to treat a variety of conditions including various forms of lymphoma, leukemia, anemia, myeloma, and autoimmune disorders.
HSCT therapy in MS involves high-dose immunosuppressive therapy (HDIT) followed by autologous hematopoietic cell transplantation (HCT). Basically, a patient’s immune system is “rebooted” with their own stem cells after having had the immune system “wiped out.” First, autologous hematopoietic stem cells are collected from a patient’s bone marrow or peripheral blood. The patient’s immune system is depleted and then the stored stem cells are reintroduced through transfusion. The new stem cells migrate to the bone marrow and over time produce new cells that eventually repopulate the body with an immune system that is less likely to attack the central nervous system.
The best known clinical trial investigating this therapy - the High-Dose Immunosuppressive Therapy and Autologous Hematopoietic Cell Transplantation for Relapsing-Remitting Multiple Sclerosis (HALT-MS) - released their 3-year interim report earlier this year. Among 24 individuals with RRMS who underwent HDIT/HCT treatment, 90.9 percent were progression free and 86.3 percent were relapse free at 3 years post procedure. These interim results are impressive; however, there are anecdotal reports from select participants in the HALT-MS trial who have reported disease activity which returned after the 3-year mark.
What is mesenchymal stem cell (MSC) therapy?
Mesenchymal stem cells (MSCs) are adult stem cells traditionally found in the bone marrow, but which can also be isolated from other tissues including cord blood, peripheral blood, and fat tissue. With MSC therapy, an individual’s immune cells are not destroyed or replaced. Instead, an individual’s mesenchymal stem cells are isolated from the bone marrow, blood or other tissues and cultured in the lab to increase their purity and numbers, and then re-introduced into the body by intravenous (into the vein) or intrathecal (into the cerebrospinal fluid) injection.
The Tisch MS Research Center of New York is conducting a phase 1 clinical trial of autologous, mesenchymal stem cell-derived neural progenitor cells (MSC-NPs) in 20 progressive MS patients. This trial is the first of its kind to be conducted in the US. In this study, MSC-NPs will be administered in multiple rounds directly into the cerebrospinal fluid in order to target regenerative mechanisms in the central nervous system.
What other types of stem cells have potential to repair MS damage?
Researchers are learning ways to grow oligodendrocyte progenitor cells (OPCs), a specialized type of stem cell that resides in the brain and conducts natural repair in response to damaged oligodendrocytes which are the cells that create myelin. Scientists are growing and expanding OPCs in lab dishes as a potential source for transplantation into MS patients.
Induced pluripotent stem cells (iPSCs) are cells that have been genetically reprogrammed back into an embryonic-like pluripotent state. iPSCs are adult cells derived from skin, blood, or other tissues, that are grown in the lab. When taken from one’s own body, it’s possible that iPSCs would not be rejected by the person’s immune system after transplantation.
More helpful articles:
Nash RA, Hutton GJ, Racke MK, et al. High-dose immunosuppressive therapy and autologous hematopoietic cell transplantation for relapsing-remitting multiple sclerosis (HALT-MS): a 3-year interim report. JAMA Neurol. 2015 Feb;72(2):159-69. doi: 10.1001/jamaneurol.2014.3780.
FDA Approves MSC-NP Therapy as Investigational New Drug in MS Clinical Trial: A Research Milestone [press release]. Tisch MS Research Center of New York. Accessed December 20, 2015.
International Conference Held by National MS Society and ECTRIMS to Assess Progress and Define Research Directions for Cell-Based Therapies for MS. National MS Society. December 9, 2015.
Stem cells and MS. National MS Society. Accessed December 20, 2015.